An image sensor is an integrated circuit containing an array of pixel sensors. Each pixel sensor includes a photodetector and an amplifier. One type of image sensor utilized in mobile devices is a CMOS formed image sensor. Such image sensors are relatively low cost compared with other types of image sensors, such as CCD sensors.
A typical CMOS based pixel sensor includes a photodetector, a reset transistor, a transfer transistor and a select transistor. The select transistor permits selection of individual pixel sensors. When a reset transistor and a transfer transistor are turned ON, the photodetector is cleared of integrated charge and then collects charge based on an image being sensed. The charge is converted to a digital value and is then provided as information representing a pixel of the image being sensed.